Lewis acids have been disclosed in U.S. Pat. No. 3,763,217 as being suitable catalysts for reacting an organic carbonate with an aromatic amine to prepare carbamates.
It has been unexpectedly discovered that certain zinc, tin and cobalt salts which are relatively inactive as catalysts for promoting the reaction between organic carbonates and aromatic amines at temperatures of 80.degree.-190.degree. C. are active at temperatures of at least 200.degree. C.